Height above average terrain

==Zone layouts==
Zone I (the most densely populated zone) consists of the entire land masses of the following states: [[Connecticut]], [[Delaware]], [[Illinois]], [[Indiana]], [[Maryland]], [[Massachusetts]], [[New Jersey]], [[Ohio]], [[Pennsylvania]], [[Rhode Island]], and [[West Virginia]]; in addition to the northern and eastern portions of [[Virginia]]; the areas of [[Michigan]] and southeastern [[Wisconsin]] south of 43° 30' north latitude; the coastal strip of [[Maine]]; the areas of [[New Hampshire]] and [[Vermont]] south of 45° north latitude; and the areas of western [[New York (state)|New York]] south of 43° 30' north latitude and eastern New York south of 45° north latitude. In addition, Zone I-A (FM only) consists of all of [[California]] south of 40° north latitude, [[Puerto Rico]] and the [[United States Virgin Islands|U.S. Virgin Islands]] (If the dividing line between Zones I and II runs through a city, that city is considered to be in Zone I.).

Zones I and I-A have the most [[Grandfather clause|"grandfathered"]] overpowered stations, which are allowed the same extended coverage areas that they had before the zones were established. One of the most powerful of these stations is [[WBCT]] in [[Grand Rapids, Michigan]], which operates at 320,000 watts and 238 meters (781&nbsp;ft) HAAT.

Zone III (the zone with the flattest terrain) consists of all of [[Florida]] and the areas of [[Alabama]], [[Georgia (U.S. state)|Georgia]], [[Louisiana]], [[Mississippi]], and [[Texas]] within approximately {{convert|241.4|km|mi|sp=us}} of the [[Gulf of Mexico]].

Zone II is all the rest of the Continental United States, [[Alaska]] and [[Hawaii]].